The present invention relates to fiber reinforced plastic drive shafts and a method of manufacturing thereof. More specifically, it relates to light-weight fiber reinforced plastic drive shafts capable of transmitting a large torque while effectively absorbing vibrations.
It has been known to the public that drive shafts of vehicles may be partly formed by light-weight fiber reinforced plastic tubes for reducing their weight. Plastic drive shafts of this kind are fiber reinforced plastic tubes having metal joints adhered to one or both ends therof, which joints are to be connected to driving shafts or driven shafts. When torque is transmitted through such a shaft, it tends to concentrate on the adhesive interfaces between the metal joints and the plastic tube. Accordingly, the adhesive interfaces are required to have sufficient torsional strength.
It is also desired that drive shafts have sufficient capability of damping vibrations in both axial and circumferential directions. Such damping effect of the drive shafts enables passengers to enjoy a better ride.
There are conventionally known a method of manufacturing a plastic drive shaft which comprises inserting joint members into the end portions of an uncured plastic tube, winding a tape around the outer surface of each end portion of the plastic tube to compress the plastic tube toward the joint member received therein, and curing the plastic at room or elevated temperatures. This plastic drive shaft, however, does not have sufficient torsional strength at the adhesive interfaces between the plastic tube and the joint members. In addition, the tape should be removed off after the curing, which makes this method lengthy.
Japanese Patent Application No. 57-98654 filed on June 9, 1982 by the same assignees is directed to a method of manufacturing a fiber reinforced plastic drive shaft comprising providing a pair of spaced tubular joint members on a mandrel, applying an adhesive onto the joint members, helically winding resin-coated continuous fibers around the joint members and the mandrel extending therebetween while rotating them integrally, helically winding resin-coated second fibers around portions of the resin tube at room or high temperatures while at the same time bonding the resin tube to the joint members. The compressing layer formed over the joint member contains continuous fibers wound at an angle of 80-90 degrees to the axis of the drive shaft, while the underlying plastic tube contains continuous fibers wound at 30-60 degrees, most preferably at 45 degrees. This fiber reinforced plastic drive shaft is, however, provided with a relatively thick compressing layer to show sufficient torsional strength at the interface between the joint member and the plastic tube. This is still a problem to be solved for the purpose of reducing the weight. Further, damping effect is not taken into consideration.